Door-knob.



N0. 699,5l5. Patented May 6, I9 02. W. F. GILBERT.

DOORKNOB.

(Application filed Feb. 17, 1902.)

(No Model.)

mini

JIHWHIL.

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Unrrnn TATES FFroE.

WILBUR F. GILBERT, OF NEIV BRITAIN, CONNECTICUT, ASSIGNOR TO P. dr F.CORBIN, OF NEW BRITAIN, CONNECTICUT, A CORPORATION OF CONNECTICUT.

DOOR-KNOB.

SPECIFICATION forming part of Letters Patent No. 699,515, dated May 6,1902. Application filed February 17 1902. Serial No. 94,373. (No model.)

To ctZZ whom it may concern:

Be it known that I, WILBUR F. GILBERT, a citizen of the United States,residing at New Britain, in the county of Hartford, State ofConnecticut, have invented certain new and useful Improvementsin'Door-Knobspf which the following is a full, clear, and exactdescription.

My invention relates to door-knobs.

Among the main objects of my invention are simplicity and economy ofconstruction, strength, and durability.

In the drawings, Figure l is a section of an incomplete portion of theknob, showing the cover or envelop constituting the outer surface of theknob proper in dotted outline. Fig. 2 is a plan view of what is shown insolid lines, Fig. 1. Fig. 3 is alongitudinal section of the finishedarticle. Fig. 4 is a side elevation of the finished article.

A is a shank, which may be formed of any suitable material, having theusual central spindle-passage. B is a flange thereon. The upper part ofthe flange constitutes a bearing-shoulder B for the outer envelop orcover of the knob. Between the bearing-shoulder B and thespindle-opening is a slightly-elevated portion constituting anothershoulder, upon which rests a mandrel C.

B is an expanded flange adjacent the spindle-opening, setting over themandrel C and holding it firmly to its supporting-shoulder upon theinner end of said shank.

The parts thus far described are shown in Fig. 1, and it will beobserved that the edge of the flange B is turned down slightly for thepurpose hereinafter described.

In Fig. 2 it is shown that the preferable form of the flange B isangular, so that by shaping the central opening in the lower side of themandrel C correspondingly the said mandrel will not turn on the shank inuse. The mandrel C is preferably made of iron or steel of properthickness to afford asufficient foundation upon which to finally shapethe outer envelop. To that end the mandrel (J is more than cup-shaped,by which I mean its upper edge is turned in to form a' top opening ofgreater diameter than the opening in the lower part of said mandrel, yetof lesser diameter than the full diameter of said mandrel. Thisconstruction prevents theknob from becoming telescoped, the saidinturned outer end of the said mandrel being suffioiently strong to givea firm support and inner foundation to said envelop D. The opening inthe upper side of the mandrel C gives access to that portion of theshank A which is turned down into the flange B Vhen the mandrel C hasbeen secured in place, a cupshaped envelop, approximating incross-section the outline shown by the dotted lines in Fig. 1, isslipped onto the mandrel, and the edge of said cup-shaped envelop isdrawn in in any suitable Way, so that it finally assumes the shape shownin Fig. 3, in which it will be observed the edge of the envelop projectssufliciently far in toward the shank A that when the flange B is turnedup against said envelop the said shoulder B will engage therewith, whilethe edge of said flange will close the space between the parts andfirmly unite said parts and give a finished graceful appearance to theproduct, as shown in Fig. 4.

Not only during the operation of the forming of the knob is the mandrelC useful, in that it prevents the improper shaping of the envelop, butafter the article is-complete it prevents the telescoping or bruising ofthe shell or envelop and reinforces and strengthens the knob, so thatfairly thin material may be employed in making the shell or envelop,thus resulting in economies Without the sacrifice of strength anddurability.

What I claim is- A door-knob comprising,a shank,asupporting-shoulderthereon, a mandrel bearing upon said supporting-shoulder a portion ofsaid shank being flanged inside of said mandrel to secure the same inplace, the outer edge of said mandrel being turned inwardly said mandrelforming front and rear bearing-surfaces, an envelop for said mandrel, aflange on the knob-shank said flange bearing against the inner edge ofsaid envelop.

Signed at New Britain, Connecticut, this 12th day of February, 1902.

WILB UR F. GILBERT.

